blake2s: fix build constraints

Having a trailing comma before a space doesn't mean that the next option
will be ANDed rather than ORed. This worked with the standard toolchain
because the filenames prevented the incorrect build constraints for
other platforms from being acted on.

Change-Id: Iaee5b60a7496166f23fc36319abe07c7a7ec04e5
Reviewed-on: https://go-review.googlesource.com/32311
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

blake2s/blake2s_386.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build 386, !gccgo, !appengine
+// +build 386,!gccgo,!appengine
 
 package blake2s
 

blake2s/blake2s_386.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build 386, !gccgo, !appengine
+// +build 386,!gccgo,!appengine
 
 #include "textflag.h"
 

blake2s/blake2s_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64, !gccgo, !appengine
+// +build amd64,!gccgo,!appengine
 
 package blake2s
 

blake2s/blake2s_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64, !gccgo, !appengine
+// +build amd64,!gccgo,!appengine
 
 #include "textflag.h"
 

blake2s/blake2s_ref.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64,!386, gccgo, appengine
+// +build !amd64,!386 gccgo appengine
 
 package blake2s